When using Android Camera, QVideoFrame bits are upside-down

I'm reading video frame contents on Android by mapping the QVideoFrame (inside QAbstractVideoFilter). The contents is flipped upside-down.

The supplied QVideoSurfaceFormat's scanLineDirection() reports that the lines should be ordered top-to-bottom.

I've attached a simple test app, which computes the relative brightness of the top & bottom parts of the frame, displaying colored bars. The reported values are fine on Linux (UVC camera), but flipped on Android.

Also please note that it's not an issue of taking Camera.orientation into account. In the test app, the VideoOutput's autoOrientation is disabled, and I align the screen orientation to match the camera orientation by looking at the video output.